The documentation for itertools.product at: https://docs.python.org/3/library/itertools.html#itertools.product
currently says that:

    For example, product(A, B) returns the same as ((x,y) for x in A for y in B)

While this is broadly correct, since product first converts its arguments to tuples, this is not true if A or B are infinite iterables. For example, when A = itertools.count() and B = range(2) then the former runs forever using infinite memory, whereas the latter returns the lazy generator immediately for use.

Would it be clearer / more correct to instead say:

    For example, product(A, B) returns the same as ((x,y) for x in tuple(A) for y in tuple(B))